Nicky Phillips and Liam Phillips

NASA successfully landed its $2.5 billion Mars Science Laboratory and Curiosity rover on the surface of the Red Planet, marking the most ambitious attempt to reach Mars in history.

"Touchdown confirmed," said a member of mission control at NASA's Jet Propulsion Laboratory as the room erupted in cheers. "We are wheels down on Mars. Oh, my God."

A dusty image of the rover's wheel on the surface, taken from a rear camera on the vehicle, confirmed the arrival of the car-sized rover and its sophisticated toolkit designed to hunt for signs that life once existed there.

Related Content

A second image arrived within seconds, showing the shadow of the rover on Mars.

When the landing was announced after a tense, seven-minute process known as entry, descent and landing, the room filled with jubilation as the mission team cheered, exchanged hugs and chief scientists handed out Mars chocolate bars.

Advertisement

President Barack Obama described the feat as a singular source of American pride.

"The successful landing of Curiosity - the most sophisticated roving laboratory ever to land on another planet - marks an unprecedented feat of technology that will stand as a point of national pride far into the future," he said in a statement.

"It proves that even the longest of odds are no match for our unique blend of ingenuity and determination."

Charles Bolden, the NASA administrator, echoed that sentiment and applauded all the nations who contributed to science experiments on board the rover.

"It is a huge day for the nation, it is a huge day for all of our partners who have something on Curiosity and it is a huge day for the American people," Bolden said.

Obama's science adviser John Holdren described the landing as "an enormous step forward in planetary exploration. Nobody has ever done anything like this. We are actually the only country that has landed surface landers on any other planet," he told NASA television.

"But this lander is vastly bigger, vastly more capable and much more complicated to bring in," he added. "It was an incredible performance."

However, success was anything but certain with this first-of-its-kind attempt to drop a six-wheeled chemistry lab by rocket-powered sky crane on an alien planet. NASA's more recent rover dropoffs were done with the help of airbags.

In the final moments, the spacecraft accelerated with the pull of gravity as it neared Mars' atmosphere, making a fiery entry at a speed of 21,240km/h and then slowing down with the help of a supersonic parachute.

After that, an elaborate sky crane powered by rocket blasters kicked in, and the rover was lowered down by nylon tethers, apparently landing upright on all six wheels.

Scientists do not expect Curiosity to find aliens or living creatures. Rather they hope to use it to analyze soil and rocks for signs that the building blocks of life are present and may have supported life in the past.

The project also aims to study the Martian environment to prepare for a possible human mission there in the coming years.

It has already been collecting data on radiation during its eight and a half month journey following launch in November 2011 from Cape Canaveral, Florida.

Earlier on Sunday, Mars program director Doug McCuistion called the science "absolutely crucial" to finding out if humans are alone, how Mars evolved from a wet to a dry planet and how accessible Mars may be for human explorers in the future.

"If we succeed, it will be one of the greatest feats in planetary exploration ever," he told reporters. "Our success rate has been pretty darn good recently."

Attempts by global space agencies since 1960 have resulted in a near 40 per cent success rate in sending landers, orbiters or other spacecraft for flybys to Mars. NASA has the best record.

4.30pm: The NASA press conference has been overwhelmed by a bevvy of scientists in matching blue polo shirts, as the entire mission control team is welcomed into the room. High fives flow and more whoops of joy.

It's going to be party time at NASA HQ tonight baby!

4.25pm: The emotion in the room at NASA mission control was palpable in the moments before and after Curiosity touched down. This photo of NASA administrator Charles Bolden pretty much sums it up:

4.08pm: Nicky Phillips at Tidbinbilla: There was rapturous applause here. Everybody was shocked the landing went off without a hitch. There was even loud applause when the first low resolution pics of Mars arrived. We're all now waiting for the press conference.

Glen Nagle the head of public relations from the tracking station is now taking questions from the floor before the press conference.

Someone asked if Canberra's antennae were in contact with Curiosity the whole way. Answer: yes, right until the final stages when the Odyssey orbiter took over.

Megan Clark, the head of the CSIRO, has just arrived in the visitors' centre having travelled up for the big event.

4.06pm: US President Barack Obama has been straight on to Twitter to pass on his congratulations:

"Tonight, on the planet Mars, the United States of America made history."—President Obama

3.32pm: WE HAVE CONTACT WITH CURIOSITY. The NASA room goes wild, with lots of high fives and hugs as they get confirmation Curiosity has sent back its first signals from Mars.

3.28pm: The NASA technicians are looking very happy. They have got a signal, but no data as yet...

3.20pm: We are now entering one of the most talked about aspects of this mission - the Seven Minutes of Terror (nice work on the branding there, NASA!).

We could explain it to you ourselves, but Captain Kirk himself - William Shatner - carries a little more gravitas:

Turn off auto-refresh at the top of the screen before playing this video.

If you can't watch the video, the basic principle is this: From entry to landing should take about seven minutes. But as there is a 14-minute delay sending a signal between Mars and Earth, scientists won't be able to listen to the landing in real time.

Here is what they are hoping is happening:

ENTRY. SEVEN MINUTES BEFORE LANDINGAt entry the spacecraft will be travelling at 21,240km/h or 5900 metres per second. Between now and the final stage of its descent the craft needs to slow down to 2.7 kilometres per hour or 0.75 metres per second.

The friction caused by this deceleration will create extreme heat, which is why the front of craft is protected by a heat shield made of phenolic impregnated carbon ablator (PICA) which was invented by the NASA Ames Research Centre.

The heat shield will be experiencing its highest temperatures (about 2100 degrees Celsius) about 75 seconds after entry. The craft will then drop another six 25-kilogram weights to shift the centre of gravity back before the parachute portion of the decent. As the spacecraft enters the atmosphere it will be travelling eastward towards the landing site for about 630 kilometres.

TWO MINUTES AND 50 SECONDS BEFORE LANDINGThe parachute deploys. It's 16-metres across and will further decelerate the spacecraft. The craft is still travelling about 1448km/h on deployment.

TWO MINUTES AND 20 SECONDS BEFORE LANDINGThe heat shield separates and falls to the surface. By now the craft is travelling 450km/h.

50 SECONDS BEFORE LANDINGThe back shell with the parachute attached separates from the descent stage and the rover. The craft is now just 1.6 kilometres from the Martian surface. But it is still travelling at 80 metres per second which is too fast for a safe landing so eight retrorockets on the decent stage of the craft begin firing. The probe then decelerates to 0.75 metres per second in preparation for a powered descent.

20 to 12 SECONDS BEFORE LANDINGFour of the eight engines shut off. At about 20 metres above the ground the rover is then lowered from the descent stage on nylon cords, known as the "sky crane maneuver". The rover's wheels and suspension system pop into place.

TOUCHDOWN: 416 SECONDS AFTER ENTRYWhen the rover senses touchdown, the nylon cords severe and the descent stage flies away and lowers onto the surface some 150 metres from the rover.

DAY ONE ON MARSIf all goes well with the landing, the rover's computers switch from entry, descent and landing mode to surface mode.

3.15pm: Poor old NASA cops a lot of flak for losing space probes on Mars, but not all of it is richly deserved. NASA actually has a pretty good track record - out of seven landing attempts, only one has failed.

Also, landing on Mars is tricky. One of the main reasons is its thin atmosphere. There is not enough atmosphere to slow a descending spacecraft down and too much for it to avoid burning up on entry. Of the 40 or so attempts to reach Mars, only about half have succeeded.

Here's a good piece from The Guardian'sStuart Clark about why the stakes for this landing and mission are high.

From about 10 minutes before entry into the atmosphere to the landing, the craft goes through six different vehicle configurations and fires 76 pyrotechnic devices so parts can separate or be deployed.

The final phase - called the entry, descent and landing - will begin when the spacecraft hits the top of the planet's atmosphere. As Curiosity descends it will fall below the Mars' horizon and so will be out of direct contact with Canberra's tracking station, which is why its landing has to be automatic.

3.05pm: Scientists from all over the world toiled about where the rover should land on Mars. In the end they decided on the 150-kilometre wide Gale Crater partly because it used to contain one of the basic ingredients for life. It was wet.

Marion Anderson, an Australian researcher who helped pick out the landing site, told the Herald's Science Editor Deborah Smith last month: "The rover will effectively have mountain ranges on each side of it".

Observations from NASA's Mars Reconnaissance Orbiter mapped the types of minerals found in the crater and detected clay minerals - which form under conditions with sufficient liquid water. "The rocks are clay-rich, which means organic material will have been preserved," said Ms Anderson.

The crater is named after the amateur Australian astronomer Walter Gale.

3pm:Nicky Phillips at Tidbinbilla: It's standing room only in the vistors centre at Tidbinbilla tracking station. Some people have been here since 9am when the centre opened. The crowd is watching the NASA live stream on the big screen. It's now less than 40 minutes until the landing.

2.50pm: Unless you have been living under a rock, you would know that Australia is playing a key role in the mission. The alignment of Earth to Mars during Curiosity's descent means Australia is in a unique position to communicate directly with the probe.

Just outside Canberra three antennas, which form part of NASA's Deep Space Network, will be sending and receiving signals from Curiosity until just before it lands. (Deep space is anywhere beyond Earth's orbit.) Check out what the antennae are doing right now.

As well Canberra's Deep Space Communication Complex (with one 70 metre antenna and two 34 metre antennae), there are similar facilities in Goldstone, California and outside Madrid, Spain. This network provides two-way radio contact with robotic spacecraft like Curiosity and space telescopes.

The data is encoded in digital form and carried by radio waves via the antennae to and from Earth. When signals are received they are relayed by fibre optic cable to Jet Propulsion Lab (JPL) in California, where it is converted into data and images.

The Canberra tracking station, which is managed on NASA's behalf by the CSIRO, will be the prime tracking station for Curiosity's landing. The Parkes radio telescope in NSW and another antennae near Perth will provide backup.

During the final part of the decent the craft will lose contact with Earth and so send signals via the Mars Odyssey orbiter, which will hover above the landing site.

The spacecraft will communicate with the Canberra tracking station through a series of distinct tones, which signify various steps in the landing process have been activated.

The director of the Canberra's Deep Space Communication Complex, Dr Ed Kruzins, told the Herald: ''We'll be carrying the signals as the spacecraft passes through the atmosphere, descends on its parachutes, fires its thrusters and lands on the surface.''

2.45pm: But seriously, Curiosity is quite the feat of engineering. As a mobile laboratory, it is fitted with 10 highly sophisticated experiments including:

mast-mounted instruments to survey its surroundings.

instruments on a robotic arm will be able to carry out close-up inspections.

lab instruments inside the rover can analyse samples from rocks, soils and the atmosphere.

it also carries a weather station.

Curiosity will be powered by batteries and a nuclear-powered generator. Each day NASA scientists will make daily decisions on the rover's activities for the next day.

Curiosity won't be able to detect active processes that would signify present-day life, nor does it have the ability to image micro-organisms or their fossil equivalents. If the rover does locate sites that had favourable conditions for habitability and for preserving evidence of life, those findings will shape future missions.

The mission will last one Mars year (98 Earth weeks - or just under two years).

2.37pm: Anyone wanting to hear how the mission is going from the little fella himself, Curiosity has its own Twitter account - @MarsCuriosity - and is managing to tweet regularly while navigating a complicated interstellar landing operation. Not bad work that.

And here's the robot itself. Is it just me or does it bear a striking resemblance to Number Five from the Short Circuitmovies...?

2.32pm: Now let's get a few things straight - Curiosity's mission is NOT to find life on Mars. Anyone hoping for it to beam back photos of little green men will be sorely disappointed.

Curiosity's main aim will be to gather evidence about whether Mars has ever been habitable. Three conditions are considered crucial for life to exist as we know it:

liquid water

organic molecules

energy source

Past NASA missions have concluded that at some point the Red Planet did have a liquid ocean, so Curiosity's focus will be searching for evidence of the other two ingredients - organic molecules, which contain carbon, and energy. Organic molecules can exist without life, but life as we know it cannot exist without them, so their presence would be an important clue for past habitability.

Energy could come from sunlight, heat or mixtures of chemicals. The info Curiosity collects from minerals could give clues for possible past or present energy sources. But the rover won't be looking directly for life in the form of fossilised micro-organisms. Think of Curiosity's trip as a prospecting mission.

Curiosity's chief project scientists, John Grotzinger, said of the mission: "We're not looking for life. We don't have the ability to detect life if it was there. We are looking for the ingredients of life."

Here's a great blog piece by astronomer and journalist Stuart Clarke from The Guardian about why Curiosity isn't directly looking for life.

2.25pm: Hello and welcome to our coverage of the final descent of Curiosity, the latest spacecraft sent from Earth to Mars in the hope to unlock more secrets of our closest space neighbour.

We will be keeping you up to date with the action both from the newsroom and on the ground at the Canberra Deep Space Communication Complex in Tidbinbilla, ACT, where Herald science reporter Nicky Phillips and video journalist Chris Hammer will be sitting alongside white-knuckled scientists as the distant probe makes its rapid landing through the Martian atmosphere.

Nicky Phillips at Tidbinbilla: The crowd is starting to grow here at the Canberra deep space tracking station at Tidbinbilla. Word from the control room is that Curiosity is on track. The two 34-metre dishes are now communicating with the Mars Odyssey orbiter and the Mars Reconnaissance Orbiter. The 70-metre dish is communicating directly with the Mars Science Laboratory - with Curiosity inside.